Abstract

Water ski jumping is one of the oldest disciplines in water skiing. The first jump was performed by Ralph Samuelson of Minnesota (US) in 1925, three years after he had invented water skiing. Samuelson jumped 18 m off the end of a greased ramp. Today water ski jumping is an international sport with elite male athletes jumping distances in excess of 70 m. The Sports Engineering Research Group (SERG) at the University of Sheffield have conducted a Computational Fluid Dynamic (CFD) analysis of the aerodynamic system of a water ski jumper for British Water Ski (BWS) in support of their 2005 World Championship campaign in China. The geometries of the water ski jumper and associated equipment were created using SERG’s in-house non-contact laser scanning facilities. Seven characteristic positional stages were analysed over the ski jump to obtain information on the fluctuations in lift and drag force acting upon the water ski jumper. The individual contribution of lift and drag, to the overall aerodynamic system of the water ski jumper, from each modeled component could be determined by the use of CFD. This indicated that the skis generate an average of 65 % of the entire system lift and drag, with the front third of the ski’s creating up to 50 % of these forces.